A man wants to get into a night club where the bouncers test each person before they can enter. The man waits and watches.
A woman walks up to the bouncers and the bouncers say 6. The woman replies with 3 and goes in.
A small man walks up and they say 12. The man replies 6 and is admitted.
The first guy thinks he’s figured it out and walks up. They say 4 and the man replies with 2, but they don’t let him in.

What should he have said?